}
		if cerr != errIO && fw.n < 0 {
			t.Errorf("test %d, mismatching Close error: got %v, want %v", i, cerr, errIO)
		}
		if ferr != errIO && fw.n < 0 {
			t.Errorf("test %d, mismatching Flush error: got %v, want %v", i, ferr, errIO)
		}
		if fw.n >= 0 {
			// At this point, the failure threshold was sufficiently high enough
			// that we wrote the whole stream without any errors.
			return
		}
	}
}